mapping forward_way = ([
        "/quest/quest_jun/sying1"   :     "south",
        "/quest/quest_jun/sying4"   :     "south", 
        "/quest/quest_jun/syuanmen2":     "west",  
        "/quest/quest_jun/yidao"    :     "west",
        "/d/xiangyang/eastgate2"    :     "west",
        "/d/xiangyang/eastgate1"    :     "west",
        "/d/xiangyang/eastjie3"     :     "west",
        "/d/xiangyang/eastjie2"     :     "west",
        "/d/xiangyang/eastjie1"     :     "west",
        "/d/xiangyang/guangchang"   :     "west",
        "/d/xiangyang/westjie1"     :     "west", 
        "/d/xiangyang/westjie2"     :     "west",
        "/d/xiangyang/westjie3"     :     "west",
        "/d/xiangyang/westgate1"    :     "west",
        "/d/xiangyang/westgate2"    :     "west",
        "/d/bianliang/yidao1"       :     "west",
        "/d/bianliang/yidao2"       :     "west",
        "/d/bianliang/yidao3"       :     "north",
]);

mapping backward_way = ([
        "/quest/quest_jun/sying4"   :     "north", 
        "/quest/quest_jun/syuanmen2":     "north",  
        "/quest/quest_jun/yidao"    :     "east",
        "/d/xiangyang/eastgate2"    :     "east",
        "/d/xiangyang/eastgate1"    :     "east",
        "/d/xiangyang/eastjie3"     :     "east",
        "/d/xiangyang/eastjie2"     :     "east",
        "/d/xiangyang/eastjie1"     :     "east",
        "/d/xiangyang/guangchang"   :     "east",
        "/d/xiangyang/westjie1"     :     "east", 
        "/d/xiangyang/westjie2"     :     "east",
        "/d/xiangyang/westjie3"     :     "east",
        "/d/xiangyang/westgate1"    :     "east",
        "/d/xiangyang/westgate2"    :     "east",
        "/d/bianliang/yidao1"       :     "east",
        "/d/bianliang/yidao2"       :     "east",
        "/d/bianliang/yidao3"       :     "east",
        "/d/bianliang/chengmen"     :     "south",
]);